The present invention relates to a barrel assembly for an electromagnetic rail guns.
Various types of rail guns have been proposed for using electromagnetic forces to accelerate projectiles to high velocities and direct them toward targets. See, for example, U.S. Pat. No. 1,985,254.
A typical rail gun includes an elongated barrel which has a pair of longitudinally extending parallel conductors or rails disposed symmetrically about its axis. The rails are connected at their rearward, or breech ends to opposite terminals of a source of direct current. A circuit through the rails may be completed either by a conductor disposed between the rails or by a plasma arc between the rails. This results in the flow of current which generates magnetic flux between the rails. The flux cooperates with the current in the conductor or the plasma to accelerate the conductor or plasma forward between the rails. The projectile may include the conductor or may be positioned forward of the conductor or plasma arc and driven forward thereby.
In addition to accelerating the projectile forward, electromagnetic forces generated during firing of the rail gun include bursting forces which tend to push the rails outward. Additional bursting forces may result from gas pressure generated by the plasma arc within the barrel. When the rail gun is fired, the rails conduct very high electrical current and are thus heated to high temperatures while being subjected to these bursting forces. The rails may be damaged during operation of the gun, and it therefore may be desirable that the rails be removable for maintenance.
The bursting forces are comparable in magnitude to those experienced in barrels of conventional chemical explosive guns. However, the tubular containment used in such guns does not solve the problems presented by rail guns.
In the rail gun, it is desirable that the two removable rails and the adjacent insulating members fit together with very close tolerances and be tightly constrained against displacement radially outward. It is also desirable that the barrel be relatively light so that it may be moved rapidly for aiming. A typical known rail gun barrel assembly employs a large number of bolts to clamp stiff structural members about the barrel components to react bursting forces. This type of arrangement is unsatisfactory for several reasons. The weight of the clamping members and bolts is relatively high, since they are generally made of steel or the like and must be fairly heavy in order to apply the required forces to the barrel component. The structural members and bolts are also relatively expensive. In addition, adjustment of the bolts is time consuming due to their number and due to the fact that fairly precise adjustments of the bolts are necessary in order to apply the desired pressure to the barrel components.